Inspirator burner



Nov. 13, 1962 D. MEYER INSPIRATOR BURNER Filed June 7, 1960 FIG. l

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IN V EN TOR.

MEYER T D J Wm m w B ATTORNEYS United States Patent O 3,053,494 INSPIRATR BURNER David Meyer, Canton, Ollio, assignor to E. W. Bliss Company Filed .lune 7, 1960, Ser. No. 34,582 2 Claims. (Cl. 158-99) The present invention is concerned generally with gas burners and more particularly to a burner, used for furnaces or other similar combustion spaces, of the type which draws the air necessary for combustion into the burner unit from the free atmosphere without use of any pressurized air supply source.

A burner embodying the present invention in its preferred form comprises as essential components a highly refractory combustion tube having a back end wall centrally apertured to provide a central fuel gas and primary air inlet opening to the combustion space with a series of circumferentially spaced radial secondary air inlet openings just forward of the primary inlet; and a burner head assembly secured at the back end of the combustion tube including an orice member projecting into the primary inlet, a preferably integral yoke structure carrier on the oriiice member for supporting a gas nozzle tube in axial alignment with the orifice member and combustion tube, and a primary air inlet shutter or control element adjustable on the gas nozzle tube for regulation of air entering the primary air orice. Preferably a secondary air supply control element is provided in the simple form of a slideable collar which may be selectably positioned on the combustion tube to close off as required the radial secondary air inlet openings.

The burner is intended to operate from a relatively high pressure gas supply line; and the gas jet formedA by the gas nozzle and aimed centrally into the intake orifice accordingly draws primary air into the oriiice from the surrounding atmosphere, while further air is then drawn into the combustion space through the described secondary air apertures.

It is the general object of the present invention to provide a simple and improved gas burner for furnaces and other such combustion spaces operating from a high pressure gas supply, which does not require any pressurized air source to supply the air necessary for combustion.

Another object is to provide a burner of the character described adapted to attain a greater heat release or higher capacity per unit volume of combustion space than has been possible with comparable burners. A still further object is the provision of a burner of the character described having secondary air inlets into a combustion tube or space of the burner to achieve a more extensive combustion of the gas-air mixture within the burner itself than is attainable with known inspirator burners; and for attainment of an increased velocity of the flame in the burner tube, whereby it becomes possible to tire against higher back pressures in the furnace or combustion space than has hitherto been feasible with comparable burners. A still further object is a provision of a burner simple and rugged in construction, yet having excellent efficiency of operation.

Other objects and advantages of the invention will appear from the following description and the drawings wherein:

FlG. 1 is generally a longitudinal or axial section through a burner embodying the present invention;

FIG, 2 is a fragmentary view with certain parts broken away taken as indicated by the line 2 2 in FIG. l; and

FlG. 3 is primarily .an end view though partially in section taken as indicated by the line 3 3 in FIG. l.

The burner of this invention, in the preferred form shown in the drawings, is comprised of two principal ICC assemblies; the combustion tube T including a casing formed by a cylindrical metal shell and a centrally apertured disc plate 11 welded or otherwise secured in the back end of the shell, and having as the essentially functional'combustion tube structure a refractory lining 12; and the burner head assembly H. The burner head assembly includes a centrally apertured element or orifice member 15, a roughly U-shaped yoke structure 16 having an enlarged axially bored central boss 17 integrally formed on the transverse portion of the yoke 18, a gas nozzle tube 19 supported in the bore of the boss '17 in axial alignment with the orice and the combustion tube axis, and a primary air shutter member 20 slideably adjustable on the gas nozzle tube and secured by a set screw 21.

The yoke structure 1-6, as here shown, is preferably integral with the orifice member 15, the forward ends of the legs 23 of the U-shaped yoke being integrally connected with the element 15 on opposite sides of the central opening through the lateral or radial projections 24; and the entire assembly is mounted on or to the combus tion tube assembly through the integral diametrically disposed radially projecting orifice member ears or of lugs 26 which are secured by respective nuts 28 on studs 27 attached to end wall 11.

The orifice structure 15 has a generally annular cylindrical portion 15a, which extends part way through the end wall aperture 12a of the combustion tube lining, to communicate with the combustion space and opens to the free atmosphere through an outwardly divergent moderately tapered primary air orifice inlet portion 15b.

The gas nozzle tube 19 is secured in position in the boss 17 by .a set screw 30, a shoulder formed by the externally threaded tube end enlargement 19a serving as a stop conveniently assembling the nozzle tube in proper position. The opposite or inner end of the nozzle tube 19 is internally threaded to receive an easily changed endtapered gas jet orifice or spud member 31 having an extreme outer diameter corresponding to that of '19 to permit an extended range of adjustment of the shutter member Ztl. The enlargement or flange 20a at the inner end of the shutter member 2.0 provides the structure pri` marily effective in control of air flow into the orice 15.

As may be seen in FIG. l, the central aperture 12a in the outer end wall of the combustion tube lining rounds slideably mounted on the shell 10 for adjusting the eiective air intake openings of the passages 33 to control secondary air inflow, is held at adjusted position by a thumb screw 35.

Preferably the refractory liner 12 has a Very high resistance to deterioration by heat; and preferably is of a porous, absorbent structure formed according to the disclosure of U.S. Patent 2,646,376; since the porous condition of the lining conduces to a desired more extensive combustion and to easy starting of a cold burner.

Gas supplied at high pressure to the nozzle tube issues as a high velocity jet from the gas orifice member 31 in direction axial of the burner drawing air along with it from the surrounding atmosphere through the primary air inlet or orifice into the main combustion space. Air is also drawn in at the same time through the secondary air inlet openings 33 to eifect extensive burning of the gas-air mixture within the hot combustion tube itself, on

the Vorder of 25 to 30% of complete combustion. In consequence, a high flame velocity estimated to be on the order of 580 f.p.s. is attained in the combustion tube by a continuous rapid succession of explosiondike occurrences, making it possible to lire against relatively high back pressures in the furnace or combustion space; with the further consequent advantages over known similar burners of a more uniform heating, higher ame temperatures and generally more economical operation. The wide variations 'of burner heat output, usually resulting from changes in draft or back-pressure in the tired space Where conventional inspirator burners, are radically minimized.

By way of .example of the burner structure and performance, consider a unit having: a combustion tube with combustion space 12b about 25/3 inches in diameter and about 8 inches long; four secondary air inlet apertures located substantially as shown in the drawing and about one inch in diameter; a primary inlet orifice with a cylindrical inside diameter of about 11/2 inch and a maximum outer tapered inlet diameter of about 1% inches; a spud orice about 37/32 Vinch in diameter; and an overall length of only about 16% inches from mouth to gas connection,

This burner is adapted to handle natural gas supplied under pressures of 3 p.s.i. and over at a gas flow rate of from 400 cubic feet to 1,500 cubic feet of gas per hour 'for natural and mfg. gas having heating values of from 400 to 1,650 Btu. per cubic foot (gas volumes reduced to standard conditions). The eiciency of combustion attainable at the burner has run from 9S to 98% total combustion, with a heat release of from 400,000 to 1,500,000 B.t.u. per hour.

l claim:

l. A gas Vburner adapted for firing into a furnace or like combustion space comprising: a refractory-lined, metal-cased burner combustion tube having a mouth at the front end and a back end wall centrally apertured for introduction of fuel gas and primary air; said tube having a plurality of circumferentially spaced radial secondary air inlet apertures opening to the tube interior immediately adjacent said end wall; and a gas nozzle assembly including an element removably secured to the outer face of said back end Wall, and having an annular` cylindrical oriee portion extending into the aperture of the wall for substantially the thickness of the Wall, said orifice portion having a tapered inlet, a yoke portion having a collar-lil-1e apertured boss formation adapted to mount a spud bearing nozzle tube in axial alignment with and in fixed spaced relation to Vsaid orifice portion, a gas nozzle tube secured in said boss formation, a Spud threadably engaged in the end of and forming an extension of said nozzle tube spaced from said orifice portion and adapted to direct fuel gas through said oriiice portion axially toward said mouth; a slidably adjustable iiange collar on said nozzle tube as a primary air control shutter means; a secondary air control collar slidably adjustable on the exterior of the combustion tube; and the internal surface of said combustion tube being ared from said end Wall toward the said mouth.

2. The gas burner set forth in claim 1 wherein said yoke includes a pair of legs integrally secured to said orilice portion on opposite sides thereof, and further fastening means for locking said primary and secondary air control collars in predetermined locations.

References Cited lin the file of this patent UNITED STATES YEA'ENTS 1,841,465 Branche Ian, 19, 1932 1,917,897 Morse July ll, 1933 1,991,418 Rowe Feb. 19, 1935 2,059,523 Hepburn et al Nov. 3, 1936 2,333,531 Ferguson Nov. 2, 1943 FOREIGN PATENTS 376,739 Great Britain lune 30, 1932 

